1. Field of the Invention
This invention relates generally to the field of electric battery cell arrays and the like. More particularly, this invention relates to a battery holder which accommodates D-cell batteries and is suitable for substitution for conventional lantern batteries.
2. Background
Electrical battery technology has progressed rapidly over the past several years and with this progress has come an increased use of batteries as a source of power. In particular, alkaline battery technology has moved rapidly ahead with major manufacturers boasting that their products currently exhibit capacities much greater than the same product of only a year before. With this increase in battery life, cost has actually declined for popular size batteries. This is particularly true for the popular D-size battery commonly used in radios, flashlights and the like. The extremely large production volumes of such batteries provide clear benefits in the economy of scale for their manufacturers. This results in decreased prices which may be passed on to the consumer.
Unfortunately, less frequently used batteries such as the lantern size battery tend to remain relatively unchanged in design since their relatively low volumes may not justify the expense of redesign and retooling. But, with the advances of the D-cell technology, the present invention allows the lantern battery user to take advantage of these technology advances as well as the convenience of using a more readily available D-size battery.
In the past, D-cell batteries did not provide a practical solution for the lantern battery user due to a D-size battery's insufficient capacity. At this writing a typical heavy duty lantern battery produces 6.0 volts and delivers about 4.0 Amp-hours (AH). Alkaline lantern size batteries are available and deliver approximately 20 Amp-hours but are even less readily available than heavy duty lantern batteries and have a wholesale cost of approximately four times that of a heavy duty lantern battery.
The present invention allows the user to use an array of four D-size batteries which can produce about 14 Amp-hours for less than twice the cost of a simple heavy duty lantern battery (excluding the cost of the battery holder). This provides the user with about 70 percent of the capacity of an alkaline lantern battery at less than half the cost. Moreover, the conventional heavy duty lantern battery user can obtain a 250 percent increase in battery life for an increased cost of only about 67 percent. As battery technology continues to improve, the economic benefits will continue to multiply. Future advances in the field of Lithium cells as well as other technologies promise to enhance the financial attractiveness of the present invention even further.
Table 1 below shows the current large volume wholesale cost and energy data for typical batteries from which the above comparisons were derived:
TABLE 1 ______________________________________ BATTERY TYPE CAPACITY COST COST/CAPACITY ______________________________________ Heavy Duty 4.0 AH $1.20 $0.30/AH Lantern Alkaline 20.0 AH $4.50 $0.23/AH Lantern D-Cells 16.0 AH $2.20 $0.14/AH (4 in series) ______________________________________
For purposes of the present description, the term "Lantern battery" is intended to cover batteries such as the Everready.TM. Hercules model as well as batteries which are similar or equivalent. Such cells are specified, for example in military specification MIL-8-4903017(EL), which is incorporated by reference. While the present invention is not limited to batteries which rigidly meet this military specification, the specification is useful in defining the general class of batteries which are the subject of this invention and is incorporated herein solely for that purpose. This conventional lantern battern design is shown in U.S. Pat. No. 1,627,264 to Baird. The manufacture of this type of battery today does not deviate very significantly from that disclosed in this 1927 patent.
The basic design of the Baird patent is modified somewhat in U.S. Pat. No. 4,125,681 to Sjogren to accommodate shorter cells by incorporating a spacer within the top of the enclosure. Also, there is provided a jack for charging rechargeable batteries.
In U.S. Pat. No. 1,487,427 to Balderston, a lantern-like battery holder structure is shown which is adapted to accept four cells which are held in place by a strap.
None of these references show a battery holder which allows use of conventional D-size batteries in a simple mechanical design which is easily assembled with few specialized parts and which is readily stackable as the present invention. Additionally, the present invention may in some instances allow military specification D-cell batteries to be used in place of military specification Lantern batteries.